2 package MooseX::Storage::Engine;
7 # the class marker when
8 # serializing an object.
9 our $CLASS_MARKER = '__CLASS__';
23 has 'object' => (is => 'rw', isa => 'Object');
24 has 'class' => (is => 'rw', isa => 'Str');
26 ## this is the API used by other modules ...
32 # mark the root object as seen ...
33 $self->seen->{$self->object} = undef;
35 $self->map_attributes('collapse_attribute');
36 $self->storage->{$CLASS_MARKER} = $self->object->meta->name;
37 return $self->storage;
41 my ($self, $data) = @_;
44 # mark the root object as seen ...
45 $self->seen->{$data} = undef;
47 $self->map_attributes('expand_attribute', $data);
48 return $self->storage;
51 ## this is the internal API ...
53 sub collapse_attribute {
54 my ($self, $attr) = @_;
55 $self->storage->{$attr->name} = $self->collapse_attribute_value($attr) || return;
58 sub expand_attribute {
59 my ($self, $attr, $data) = @_;
60 $self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) || return;
63 sub collapse_attribute_value {
64 my ($self, $attr) = @_;
65 my $value = $attr->get_value($self->object);
68 # this might not be enough, we might
69 # need to make it possible for the
70 # cycle checker to return the value
71 $self->check_for_cycle_in_collapse($attr, $value)
74 if (defined $value && $attr->has_type_constraint) {
75 my $type_converter = $self->find_type_handler($attr->type_constraint);
76 (defined $type_converter)
77 || confess "Cannot convert " . $attr->type_constraint->name;
78 $value = $type_converter->{collapse}->($value);
83 sub expand_attribute_value {
84 my ($self, $attr, $value) = @_;
87 # (see comment in method above ^^)
88 $self->check_for_cycle_in_expansion($attr, $value)
91 if (defined $value && $attr->has_type_constraint) {
92 my $type_converter = $self->find_type_handler($attr->type_constraint);
93 $value = $type_converter->{expand}->($value);
99 # possibly these two methods will
100 # be used by a cycle supporting
101 # engine. However, I am not sure
102 # if I can make a cycle one work
105 sub check_for_cycle_in_collapse {
106 my ($self, $attr, $value) = @_;
107 (!exists $self->seen->{$value})
108 || confess "Basic Engine does not support cycles in class("
109 . ($attr->associated_metaclass->name) . ").attr("
110 . ($attr->name) . ") with $value";
111 $self->seen->{$value} = undef;
114 sub check_for_cycle_in_expansion {
115 my ($self, $attr, $value) = @_;
116 (!exists $self->seen->{$value})
117 || confess "Basic Engine does not support cycles in class("
118 . ($attr->associated_metaclass->name) . ").attr("
119 . ($attr->name) . ") with $value";
120 $self->seen->{$value} = undef;
126 my ($self, $method_name, @args) = @_;
128 $self->$method_name($_, @args)
130 # Skip our special skip attribute :)
131 !$_->isa('MooseX::Storage::Meta::Attribute::DoNotSerialize')
132 } ($self->object || $self->class)->meta->compute_all_applicable_attributes;
135 ## ------------------------------------------------------------------
136 ## This is all the type handler stuff, it is in a state of flux
137 ## right now, so this may change, or it may just continue to be
138 ## improved upon. Comments and suggestions are welcomed.
139 ## ------------------------------------------------------------------
142 # these are needed by the
143 # ArrayRef and HashRef handlers
144 # below, so I need easy access
145 my %OBJECT_HANDLERS = (
148 (exists $data->{$CLASS_MARKER})
149 || confess "Serialized item has no class marker";
150 $data->{$CLASS_MARKER}->unpack($data);
154 ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
155 || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
162 # These are boring ones, so they use the identity function ...
163 'Int' => { expand => sub { shift }, collapse => sub { shift } },
164 'Num' => { expand => sub { shift }, collapse => sub { shift } },
165 'Str' => { expand => sub { shift }, collapse => sub { shift } },
166 # These are the trickier ones, (see notes)
168 # Because we are nice guys, we will check
169 # your ArrayRef and/or HashRef one level
170 # down and inflate any objects we find.
171 # But this is where it ends, it is too
172 # expensive to try and do this any more
173 # recursively, when it is probably not
174 # nessecary in most of the use cases.
175 # However, if you need more then this, subtype
176 # and add a custom handler.
180 foreach my $i (0 .. $#{$array}) {
181 next unless ref($array->[$i]) eq 'HASH'
182 && exists $array->[$i]->{$CLASS_MARKER};
183 $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i])
190 # we need to make a copy cause
191 # otherwise it will affect the
192 # other real version.
195 ? $OBJECT_HANDLERS{collapse}->($_)
203 foreach my $k (keys %$hash) {
204 next unless ref($hash->{$k}) eq 'HASH'
205 && exists $hash->{$k}->{$CLASS_MARKER};
206 $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k})
213 # we need to make a copy cause
214 # otherwise it will affect the
215 # other real version.
218 ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}))
219 : ($_ => $hash->{$_})
223 'Object' => \%OBJECT_HANDLERS,
225 # The sanity of enabling this feature by
226 # default is very questionable.
229 # expand => sub {}, # use eval ...
230 # collapse => sub {}, # use B::Deparse ...
234 sub add_custom_type_handler {
235 my ($class, $type_name, %handlers) = @_;
236 (exists $handlers{expand} && exists $handlers{collapse})
237 || confess "Custom type handlers need an expand *and* a collapse method";
238 $TYPES{$type_name} = \%handlers;
241 sub remove_custom_type_handler {
242 my ($class, $type_name) = @_;
243 delete $TYPES{$type_name} if exists $TYPES{$type_name};
246 sub find_type_handler {
247 my ($self, $type_constraint) = @_;
249 # this should handle most type usages
250 # since they they are usually just
251 # the standard set of built-ins
252 return $TYPES{$type_constraint->name}
253 if exists $TYPES{$type_constraint->name};
255 # the next possibility is they are
256 # a subtype of the built-in types,
257 # in which case this will DWIM in
258 # most cases. It is probably not
259 # 100% ideal though, but until I
260 # come up with a decent test case
261 # it will do for now.
262 foreach my $type (keys %TYPES) {
264 if $type_constraint->is_subtype_of($type);
268 # the reason the above will work has to
269 # do with the fact that custom subtypes
270 # are mostly used for validation of
271 # the guts of a type, and not for some
272 # weird structural thing which would
273 # need to be accomidated by the serializer.
274 # Of course, mst or phaylon will probably
275 # do something to throw this assumption
276 # totally out the door ;)
280 # if this method hasnt returned by now
281 # then we have no been able to find a
282 # type constraint handler to match
283 confess "Cannot handle type constraint (" . $type_constraint->name . ")";
294 MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
298 No user serviceable parts inside. If you really want to know, read the source :)
320 =item B<expand_object>
322 =item B<collapse_object>
330 =item B<collapse_attribute>
332 =item B<collapse_attribute_value>
334 =item B<expand_attribute>
336 =item B<expand_attribute_value>
338 =item B<check_for_cycle_in_collapse>
340 =item B<check_for_cycle_in_expansion>
342 =item B<map_attributes>
346 =head2 Type Constraint Handlers
350 =item B<find_type_handler>
352 =item B<add_custom_type_handler>
354 =item B<remove_custom_type_handler>
368 All complex software has bugs lurking in it, and this module is no
369 exception. If you find a bug please either email me, or add the bug
374 Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
376 Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
378 =head1 COPYRIGHT AND LICENSE
380 Copyright 2007 by Infinity Interactive, Inc.
382 L<http://www.iinteractive.com>
384 This library is free software; you can redistribute it and/or modify
385 it under the same terms as Perl itself.